Preview

Linux

Powerful Essays
Open Document
Open Document
904 Words
Grammar
Grammar
Plagiarism
Plagiarism
Writing
Writing
Score
Score
Linux
Linux - The shell
-------------------------------------------------
Introduction to the shell
The command interpreter is the interface between the user and the operating system, hence the name "shell".

The shell therefore acts as an intermediary between the operating system and the user thanks to command lines that are entered by the latter. Its role consists in reading the command line, interpreting its meaning, carry out the command, and then return the result via the outputs.
The shell is an executable file responsible for interpreting the commands, transmitting them to the system, and returning the result. Ther are several shells, the most common being sh (called "Bourne shell"), bash ("Bourne again shell"), csh ("C Shell"), Tcsh ("Tenex C shell"), ksh ("Korn shell"),and zsh("Zero shell"). Their name generally matches the name of the executable.
Each user has a default shell, which will be launched upon opening of a command prompt. The default shell is specified in the dans configuration file /etc/passwd in the last field of the line corresponding to the user. It is possible to change the shell during a session by simply executing the corresponding executable file, for example: /bin/bash
-------------------------------------------------
Prompt
The shell is initialized by reading its overall configuration (in a file of the directory /etc/), followed by reading the user's own configuration (in a hidden file whose name starts with a dot, located in the basic user directory, i.e. /home/user_name/.configuration_file). Then, a prompt is displayed as follows: machine:/directory/current$
By default, for most shells, the prompt consists of the name of the machine, followed by two points (:), the current directory, then a character indicating the type of user connected: * "$" speciies a normal user * "#" specifies the administrator, called "root"
-------------------------------------------------
The command line

You May Also Find These Documents Helpful

  • Better Essays

    Nt1310 Unit 4

    • 3614 Words
    • 15 Pages

    If the following program (myprog) is run from the command line as myprog 1 2 3, What would be the output?…

    • 3614 Words
    • 15 Pages
    Better Essays
  • Good Essays

    Unix processes are instances of an executed program. UNIX, being a multi task operating system handles thousands of processes at a time. We are able to check on what processes are currently running by typing ps at the UNIX prompt. Depending on the options used with the ps command, we can see different outcomes such as $ps -ef | more. This will list all the processes in the system. Some items you might see using the ps command are PID which is the process ID number, TT or TTY shows the controlling terminal for the process. If there is no controlling terminal then a question mark is used.…

    • 567 Words
    • 3 Pages
    Good Essays
  • Satisfactory Essays

    NT1310 Unit 3 Homework

    • 1253 Words
    • 5 Pages

    A1) The shell goes to “sleep” until the command has been processed. You can run a program in the background, which will allow you to run more than one at a time.…

    • 1253 Words
    • 5 Pages
    Satisfactory Essays
  • Powerful Essays

    NT1430 Lab2 Joy Brewer

    • 989 Words
    • 4 Pages

    4. What is a Process? A process is the execution of a command by Linux (they can communicate with each other) What Utility provides communication between processes where output of one process provide input for another? pipe…

    • 989 Words
    • 4 Pages
    Powerful Essays
  • Powerful Essays

    Unit 3 network discovery

    • 1031 Words
    • 5 Pages

    The shell tries to find an executable program with the same name as the command. When it does, the shell executes the program. When finishing the command put an & ampersand symbol at the end of the command and the command will run in the background. Then a cursor will be displayed immediately to allow the next command to be entered.…

    • 1031 Words
    • 5 Pages
    Powerful Essays
  • Satisfactory Essays

    NT1430

    • 369 Words
    • 2 Pages

    Bash is a unix based shell created by a programmer named Brian Fox while he worked for the Free Software Foundation. Bash is an acronym for Bourne-again shell. It is a reference to its initial purpose, to serve as a free open-source version of the Bourne Shell. However, bash has grown into its own shell, and is currently the default shell for most linux kernels and mac OS X.…

    • 369 Words
    • 2 Pages
    Satisfactory Essays
  • Satisfactory Essays

    Depending on the users OS setup, X is automatically after other daemons are started. 6. Why would you place /var at the start of the disk?…

    • 680 Words
    • 10 Pages
    Satisfactory Essays
  • Good Essays

    Unit 16 Ao1

    • 529 Words
    • 3 Pages

    All programs are written to do something, their purpose may be to perform a calculation or to run a computer game, but all programs will perform a task, also known as a process. All programs take the stricter of input, process to output. Th input includes user controls such as keyboard, mouse, game controller, voice and so on. It will also include data from the user, computer or other programs.…

    • 529 Words
    • 3 Pages
    Good Essays
  • Powerful Essays

    data and can be initiated from the DOS command prompt? What useful information does this query…

    • 924 Words
    • 4 Pages
    Powerful Essays
  • Good Essays

    | The default shell is bash. The shell allows users to type commands and have the output displayed on the screen.…

    • 489 Words
    • 2 Pages
    Good Essays
  • Powerful Essays

    Shell is a piece of software that provides an interface for users of an operating system. Shell provides access to the services of a kernel. Shell makes the user’s job faster and easier in many ways.…

    • 1455 Words
    • 4 Pages
    Powerful Essays
  • Powerful Essays

    Q:What is the default directory when you open a new command window? What is your working directory?…

    • 1015 Words
    • 5 Pages
    Powerful Essays
  • Satisfactory Essays

    6. The Magic Tab: Instead of typing the whole filename if the unique pattern for a…

    • 498 Words
    • 2 Pages
    Satisfactory Essays
  • Good Essays

    In the search results, click on , which is likely to be the first item on the list.…

    • 1817 Words
    • 8 Pages
    Good Essays
  • Satisfactory Essays

    CUI v/s GUI

    • 565 Words
    • 3 Pages

    Because of the memorization and familiarity needed to operate a command line interface, new users have a difficult time navigating and operating a command line interface.…

    • 565 Words
    • 3 Pages
    Satisfactory Essays

Related Topics